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i. X. CALHOUN HYDRAULIC SLIP 2 She'ets-Sheet 1 Filed Jan. 14, 1946 INVENTOR.

1:. x. CALHQUN HYDRAULIC SLIP Filed Jan. 14, 1946 2 Sheets-Sheet 2 Patented Dec. 20, 1,949

UNITED STATES PATENT OFFICE HYDRAULIC SLIP Ingram X. Calhoun, Oklahoma City, Okla. Application January 14, 1946, Serial No. 641,148

3 Claims.

This invention relates to pip handling equipment for wells and more especially to slip actuating apparatus for rotary tables.

Heretofore, it has been necessary, in order to release the pipe suspending slips from the master bushing of a rotary table, to elevate the pipe and relieve the slips of the weight thereof whereupon the slips, weighing in some instances approximately 200 pounds, are lifted manually through the combined effort of two workmen. The great weight of the slips, together with the fact that the workmen handling the same are directly under the lifting crane and traveling block, render this type of work exceptionally strenuous and dangerous.

It is the principal object of the present invention to minimize the labor and hazard incident to the actuation of rotary slips by providing hydraulic cylinders individual to each of the usually four slips of the rotary, having pistons engageable with the slips and actuated simultaneous by pressure applied through a master valve to raise the slips so that the pipe suspended thereby may be raised and lowered.

Another object of the invention is to provide hydraulic slip actuating apparatus for rotaries which is not difiicult to install and after installation, is easily operated and further, the apparatus is equipped with a safety valve which maintains in the hydraulic system a pressure sufficient only to raise the weight of the slips, thus insuring against displacement thereof when the latter are operatively disposed to hold a string of pipe suspended in an open Well.

Still another object of the invention is to provide a hydraulic slip actuating apparatus which, by virtue of its construction and assembly it is capable of displacing and resetting slips by remote control, thus obviating all danger usually attending this operation.

With the foregoing objects as paramount, the invention has further reference to certain features of accomplishment which will become apparent as the description proceeds, taken in connection with the accompanying drawing wherein:

Figure 1 is a top plan View of a rotary table showing the hydraulic slip actuating system installed.

Figure 2 is an elevational view of Figure 1 in.

vertical section, taken through the center of the rotary table, and

Figure 3 is an elevational view of a rotary well drilling rig and derrick.

Continuing with a more detailed description of the drawings, reference is primarily made to Figure 3, wherein numeral 44 denotes a conventional derrick, on the floor of which operates a rotary table 25. A traveling block 34 is actuated by a line 38 operating over a crown block 33 from the draw-works or hoisting mechanism 39. Pipe elevator 37 is attached to the traveling block 34 through links 35 and hook 35. The elevator is adapted to latch around the tool joint l9 to lift the drill stem 23 which latter is ordinarily lifted until three joints thereof are above the derrick floor and then, each stand of three joints indicated at i2 is unscrewed and leaned against the side of the derrick in a pipe rack 43, as shown.

The equipment described in the foregoing is not a part of the present invention but is mentioned and illustrated in Figure 3 in order to. disclose the relative position thereto of the invention and its operation.

In Figures 1 and 2 is shown a rotary table having a drive shaft I, driven from the draw-works 39 of the rig. The rotary has a rotating section 2 operated by the main drive gear 3, which latter in turn is rotated by a pinion 4, mounted on the drive shaft l. Mounted in the rotating section 2 of the table is a pair of complementary sections 5 and 6, comprising the master bushing thereof.

The sections 5 and 6 of the master bushing are each provided with inclined recesses adjacent each corner but which open throughout their lengths into the circular central opening defined by these sections in which repose the segmental slips 23 which jointly serve to suspend the pipe 20 in the well.

Mounted in each of the inclined recesses of the bushing sections 5 and 6 are cylinders l which are held in secure relationship with the bushings by means of lugs 3| and bolts 32. It will be observed in Figure 1 that the slips are operable in pairs and that the slips of each pair are joined together by links 2?.

Each cylinder 1 has a piston rod 2! extensible from its lower end and a lug 2m carried by the lower end of each rod extends inwardly of the central opening 22 defined by the bushing sections 5 and 5 to lie in a recess in the slips 23. It is apparent therefore that as the rods 2| are raised and lowered by fluid pressure introduced into and exhausted from the cylinders 1, the slips 23 are correspondingly actuated. When the slips are in the position shown in solid lines in Figure 2 they are the sole support of the string of pipe in the hole, but when actuated to the position shown in dotted lines and designated by numeral 23', the drill pipe is released and the slip opening is sufiiciently large to pass the tool joint l9.

To actuate the pistons in cylinders I and consequently the rods 2|, a fluid line 8 extends from the bottom of one cylinder of a pair to the bottom of the companion cylinder of the pair and to one of the lines 8 is connected a flexible fluid line Ill and to the other line 8 is connected a flexible fluid line l2. Lines 16 and I2 are joined to a line I5 which latter, in turn, is in communication with a four way pressure control valve l8.

The upper or head end of a cylinder 1 of each pair is connected through fluid line 9 to the upper or head end of the companion cylinder oi the pair and one of the lines 9 is connected to a flexible line I I while the companion; line 9 is connected to a flexible line 13. A flexible line 14 effects communication between lines It and I3 and the four-way pressure control valve 18,

A fluid pressure line I! enters the valve 18 and a pressure return line I6 relieves pressure in lines II2 and lines II and 13 when the valve I8 is actuated, as will become apparent presently.

When valve i8 is actuated to effect communication between pressure supply line I! and line I5, fiuid pressure is imposed on the ram end of cylinder 1 through lines 10 and I2. Simultaneously, return line 16 is opened to fluid seeking release from the head ends of cylinder 1 through lines H and I3 and interconnecting line 14. Fluid pressure in line ll entering the lower ends of cylinders 1 through lines 10 and I2 from line I will cause pistons in the cylinders to move upwardly therein to raise the slips 23 to, their dotted positions at 23', through the medium of rods 2| and lugs Zia carried thereby. Fluid displaced from the heads of cylinders 1 will flow through lines H and I3, to pipe 14 and back to source through the valve 58 and line 16.

As a safety precaution, a relief valve 29 is provided to control pressure in lines In and I2. and this valve is connected to line l5 through short pipe 28 and to line l6 through short pipe 30. It.

is obvious that when the valve 29 is so set as to. permit pressure in lines and [2 just sufiicient to lift the weight of slips 23, there is little or no likelihood that the slips will become accidentally or prematurely elevated by pressure surges which would result in dropping the pipe string into the well. The drill stem or pipe 20 must be slightly raised and supported by the traveling block 34 before the slips can be hydraulically elevated to the position shown in dotted lines in Figure 2.

Referring again to Figure 3, hydraulic pressure generator 42 supplies fluid under pressure to the master valve 18 through line I! and the generator receives spent fluid returning through line I6.

The rotary table 2 is rotated by the draw- Works 39 subsequent to the removal of cylinders I through chain drive 45, which is powered by an engine 40, the said drawworks and engine being protected by a shed 4|.

As a general rule in conventional practice, the bushings of the rotary table used in drilling are removed and replaced by others more suitable for holding pipe gripping slips when running or pulling casing. In the invention, this practice remains the same, that is to say, when the hydraulic slips are being employed to hold the casing in spinning the rotary table is not used except to retain the bushings 5 and 6 and the slips. In other words, the rotary table remains stationary and the pipe is spun or rotated to make and break joints by means of the hydraulic tong described in my co-pending application Serial No. 641,147.

When the spinning operation is completed to resume drilling, the bushings 5 and 6 are removed, along with the slips 23 and the hydraulic slip actuating cylinders and replaced by conventional bushings and slips.

Manifestly, the construction as shown and. described is capable of some modification and such modification as may be construed to fallwithin the scope and meaning of the appended claims is also considered to be within the spirit and intent of the. invention.

What is claimed is:

1. In combination with a rotary table, hydraulic slip actuating apparatus comprising a pair of complementary bushings receivable in said rotary table, each having spaced apart, annular recesses therein, a series of pipe engaging slips adapted to be embraced jointly by said bushings, said slips each having a recess confronting a re,- cess in each of said bushings, a cylinder affixed in each of the joint recesses of said bushings and ,slips, a piston in each of said cylinders having a. rod, a lug aflixed to the end of each of the piston rods and entering thev recess of said slips, flexible.

lines connected to a source of fluid and to said cylinders for actuating the pistons therein to raise and lower said slips with respect to said.

"bushings and valve means for controlling the flow of fluid through said flexible lines.

2. In combination with a rotary table, cooperating bushings removably mounted in said rotary table and defining a tapered central cavity, said bushings each having spaced apart and arcuated recesses in the inner face thereof, a circular group of pipe engaging slips displaceably mounted in said central cavity, each having a recess aligned with an arcuate recess in said bushings, a cylinder secured in the upper end of each of the recesses of said bushings, a piston in each of said cylinders having a piston rod, a lug carried by each of the piston rods and receivable in a recess in each of said slips and means for supplying fluid to said cylinders to actuate said pistons and rods whereby to raise and lower said slips.

3. In combination with a rotary table, removable bushings in said rotary table defining a,

tapered central cavity, a series of displaceable slips conformably retained in the central cavity of said bushings, a series of annularly spaced cylinders interposed between the slips and bush-.

ings, each having a piston and piston rod, means carried by the lower end of each of the piston rods.

for engaging one of said slips and means oper-v REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,341,702 Black June 1,1920 1,860,062 Taylor May 24, 1932. 2,276,016 Brantly Mar. 10, 1942 

